int dts(int x) {
	int n = 0;
	while(x /= 2) n++;
	return n;
}


unsigned char * bwrite(unsigned char * encoding) {
	// assume host byte size is CHAR_BIT
	if(strlen(encoding)%CHAR_BIT != 0) {
		printf("warning: bit length is not evenly divisible against a byte, the last byte may be corrupted\n");
	}
	size_t len = strlen(encoding)/CHAR_BIT;
	unsigned char * s = malloc(len);
	memset(s, 0, len);
	
	int i;
	for( i = 0; i < strlen(encoding); i++) {
		s[i>>dts(CHAR_BIT)] |= ( encoding[i] == '1' ? 1 : 0 ) >> ((CHAR_BIT-1)-(i)&(CHAR_BIT-1));
	}
	s[len] = 0;
	return s;
}